Moles of given amount: This is where it gets tricky. Scroll down to point number 8, where you will find that the mass of the given amount is 130. To find the amount of moles in this given amount, divide the Mass of given amount (130g) by the mass of one mole of water (18.015), which will result in approximately 7.22 moles.

Number of Representative particles in given amount: This is definitely where it gets tricky. Hearken back to the 12/6/11 HW [find it here] and recall that the Particles / Androgav's # = the amount of moles, and the moles times the formula mass = the mass of the sample. Well, we're trying to get the number of particles in the given amount, so we're gonna work backwards.

Sample Equation for easier viewing:

P/A = MolMol x mbase formula = msample amount

For msample amount we can fill in as 130. For mbase formula we can fill in with 18.015. For Mol, we can fill in with 7.22. Oh, wait silly me, we've already done that! We have the moles.

So for Mol we can fill in as 7.22. For A, recall that it is androgov's or whatever his name is # which is 6.02x1023. Working backwards, multiply 7.22 by Andy's # and you'll get something similar to 4.35x1024.

Mass of given amount: This is where it gets tricky. Get the density formula, D = m/v. We know water's density is 1, and the volume (given) is 130mL. Multiple 1 by 130 to get 130g, which is in fact the mass of the given amount.